Effect of chemical properties on drug release from hydrophobic matrices

The drug release of modified release matrix systems is often governed by erosion as well as by diffusion through the matrix. The purpose of the present work was to study the release kinetic parameters of inorganic and organic water soluble drugs from hydrophobic wax matrix systems, produced by melt coating. The drug release process was investigated both experimentally and by means of mathematical models. Different models (first order, cube root, square root, two-third root) and the Weibull distribution were applied for the evaluation of the drug release data. On the basis of our results, it can be concluded that not only the ratio but the chemical characteristic of the drug and the matrix base material as well determine the rate of drug release.